IPv6 Delegated Prefix Size

I do have multiple internal interfaces, hence the desire to request a /60 which, according to multiple postings in Comcast's forums, is supported if the router includes the PD hint in the DHCPv6 request.

I've figured out that i can modify /var/chroot-dhcpc/etc/default.conf6 which is the template that the code uses to configure IPv6 on my external interface. I don't see how to change the command-line parameters being sent to dhclient6 yet. I've also found other people suggesting they can use versions of ISC dhclient6 with Comcast and pull a /60. The version of chclient6 on this machine is 4.3.0 which is pretty current.

I've done some packet captures and I'm not seeing the IAPREFIX option in the solicitation. Wondering if anyone else has figured this out.

PS: There's a feature request from 2013 somewhere on Sophos' site that suggests using another DHCPv6 package but that's a non-starter obviously for an end-user.

Any luck? i'm in a similar boat. I have multiple VLANs on my UTM and would like to hand out a PD to each of them and not just one. ATT can theoretically give me bigger subnets but the UTM seems convinced I only need a single /64. I just need ot know how to make the UTM ask for bigger

I asked on the ISC DHCP list and got nothing of use. One suggestion was to manually fiddle with the lease file but I never figured that out. Seems like it's not possible with this DHCP client. Sophos likely needs to look at using another.

as an alternative, what if the same /64 could be used on multiple lan ports? given each mac is unique and any IP concocted from the prefix will thus be unique, would that approach not suffice at least for some users?

You could do that but remember to subnet to less then /64. Also remember that the /64 is the standard smallest network size allocated except for some ISPs who allocate a /128 for your link.

You could do that but remember to subnet to less then /64. Also remember that the /64 is the standard smallest network size allocated except for some ISPs who allocate a /128 for your link.